Oil cooler



J. ASKIN OIL COOLER Deb. '3, 1940.

Filed Nov. 17, 1939 2 Sheets-Sheet l 'INVENTOR Joseph Ask 1h BY W ATTORNEY J. ASKIN OIL COOLER Filed Nov. 17, 1939 Dec. 3,- 1940..

2 Sheets-Sheet 2 INVENT R Jase ob 25km WW ATTORNEY Patented Dec. 3, 1940 OIL COOLER Joseph Askin, Bufialo, N. Y., assignor to Fedders Manufacturing Company, Inc., Buffalo, N. Y.

Application November 17, 1939, Serial No. 304,982

4 Claims.

This inventionis directed to lubricating oil coolers of the preheating type, which find their principal application in the field of aeronautics.

An object of the invention is to provide an oil cooler in which the preheating jacket or element is so advantageously positioned and devised as to provide a fully uniform heat transfer rate to all portions of the radiator elements of the cooler, with the result that localized oil blocking in remote zones of the device is rendered impossible.

It is a further object of the invention to utilize the jacket and a casing member to form receptacles and flow guides for a number of tube bundle radiator units through which the oil is directed in a series flow and at all times in intimate thermal relation with the jacket.

Other objects and advantages of the invention are more fully set forth in the acompanying specification and drawings, wherein:

Fig. 1 is a top view of the oil cooler with a portion broken away in quarter section to show the port and fitting arrangement;

Fig. 2 is a section on the line 2-2 of Fig. 1; Figs. 3 and 4 are fragmentary sections on the lines 33 and 4-4 respectively of Fig. 1;

Fig. -5 is a side elevation of the cooler with the outer shell, outer core, and fittings removed;

Fig. 6 is a diagrammatic viw showing the normal circuit for the oil through the various elements and passages of the cooler.

The oil cooler includes a skeleton structure consisting of integrated sheet metal elements forming an outer casing III, a concentrically disposed hollow jacket II, and aligned chambers I2, I3 and I4, which chambers extend from the jacket II to the casing I0, and which in eifect provide a partition splitting the outer annular space. The space within the jacket I I and the space between the jacket II and casing III are filled with tubes I5 to form inner and outer tube bundles I6 and I1 respectively. The tubes I 5 may be of a type well known in the art, having enlarged hexagonal terminals or heads I8, which permit an internesting assembly. The tube heads I8 and the enclosing jacket and casing are soldered to form in eflect a homogeneous structure, within which the tubes are closely and regularly spaced to form locular masses within the bundles I6 and IT. The jacket and casing are constructed in prismoidal form, in order to facilitate matching and soldering thereof with the geometrical arrangement of the tube heads. In aeronautical use, the oil cooler may be placed in a suitably located air duct (not shown),

so that air at high velocities is directed through the tubes. It will therefore be apparent that the geometrical configuration of the cooler may be greatly varied from the form described, as may be dictated by the shape of the duct and other aerodynamic considerations. 5

The cooler is formed in such manner that the oil is forced through the jacket and bundles in a long tortuous path without the use of numerous baflies. The oil is pumped into the cooler at a uniform pressure through an inlet conduit 20,

and it is returned through an outlet conduit 2I.. The conduit 20 is carried by a fitting 22, which fitting is soldered to the chamber I2 and communicates with such chamber through a port I2a therein. An outlet fitting 23, to which the 15 conduit 2| is attached, is secured to the chambers I3, I4, and it has two branch passages 24 and 25, which communicate with such chambers through ports |3a and Ma respectively. The passage 24 in the fitting 23 is formed with a seat '26 which is closed by a spring-pressed relief valve 21. A third port 28 is formed in the side wall of the chamber I3 and it communicates with the outer bundle I'l (Figs. 1 and 3).

The chambers I2 and I3 are formed with additional ports I21) and I3b, which communicate with the interior of the jacket II. A wall 29 (Fig. 5) separates the ports, and it is disposed within the jacket to promote uniform flow of oil therethrough. As thus far described, it will be noted that the oil is first directed about the interior of the jacket I I, whence it emerges in the chamber I3. From this location the oil may lift the valve 26 and return directly to the engine through the conduit 2|, if excessive head pressures in the bundles prohibit its flow through the port 28 (Fig. 3).

With particular reference to Fig. 6, it will be observed that under normal conditions the oil will pass through the port 28 and -it will flow 4o clockwise through the outer bundle I 'I under guidance of the confining walls of the jacket and easing. It will be noted that the flow through the bundle I1 is counter to the flow in the jacket, a condition which is most desirable 45 to produce the best heat interchange results. A pasasge 30 (Figs. 2 and 5) extends through the jacket II, and it connects the bundles I6 and I1. Thus, after the oil completes its circuit in the bundle I1, it enters the bundle I Ii through the 50 passage 30, and it is subsequently directed in a counter-clockwise flow through the bundle I6 with the aid of a diametrally positioned baille plate 3| therein (Fig. 2). The ofl is finally directed to the chamber I4, fitting passage 25, and

outlet conduit 2|, through a walled passage 32 which extends through the jacket H and connects the bundle l8 and chamber ll (Fig. 3).

In operation under low temperature conditions, it will be apparent that on starting the engine the oil will'be so viscous in the cellular passages of the bundle that passage therethrough will be blocked. In such event, the oil fiows through the jacket I l and out of the cooler through the valved seat 26. It will be observed that during this preliminary fiow the entire length of the tortuous passage formed by the bundle and casing structure is in direct heat exchange relation with the hot flowing oil. As a result, the bundles receive a rapid and uniform heating, and the viscous oil therein is rapidly brought to a fluid condition. Flow is accordingly instituted in the bundles through the normal circuit illustrated in Fig. 6, and during such occurrence the valve 21 gradually closes and the full pump discharge is eventually directed through the bundles.

In the aeronautical field, oil coolers have been subject to localized re-blocking under the severe temperature conditions encountered in actual iiight. In the present device, this is entirely eliminated, since the heat interchange action between the jacket and bundles is so uniform that no zone or section of the oil path is isolated, and as a result the entire bundle area may at all times be rapidly brought into condition for satisfying the most severe cooling demands.

I claim: V

1. In an oil cooler, a plurality of successively enclosing elements including in order, a bundle, a hollow jacket, a second bundle, and a casing, said bundles being connected by a passage, oil supply means leading into the jacket, an outlet from the jacket leading into one of said bundles, an outlet fitting on the casing communicating with the remaining bundle, and valve controlled means responsive to pressure conditions in the cooler for connecting said jacket outlet with said outlet fitting.

2. In an oil cooler, a plurality of successively enclosing elements including in order, a bundle,-

a hollow jacket, a secondbundle, and a casing, oil supply means leading into said jacket, an oil outletirom the jacket leading into said second bundle, a passage extending through the jacket and connecting said bundles, an outlet fitting on the casing communicating with the first bundle,

and valvecbntrolled means responsive to pressure conditions in the cooler for connecting said jacket outlet with said outlet fitting.

3. In an oil cooler, a plurality of successively enclosing elements including in order, an inner bundle, a hollow jacket, an outer bundle, and a casing, said outer bundle being axially split by a partition, oil supply means leading into said jacket, an oil outlet from the jacket leading into one end of the outer bundle as defined by said partition, a passage extending through the jacket and leading from the opposite end oi. the outer bundle to said inner bundle, an outlet fitting on the casing communicating with the first bundle, and valve controlled means responsive to pressure conditions in the cooler for connecting said jacket outlet with said outlet fitting.

4. In an oil cooler, a plurality of successively enclosing elements including in order, an inner bundle, a hollow jacket, an outer bundle, and a casing, a double walled structure axially splitting said outer bundle and extending from the jacket to the casing, said structure being divided into three chambers, an inlet fitting on said casing leading into one of said chambers, said chamber also communicating with said jacket, a port connecting the second chamber with thejacket, a port in said second chamber leading into said outer bundle, a passage extending through the jacket and connecting said bundles at a point remote from said last named port, an outlet fitting communicating with the third chamber, a passage connecting said third chamber with said inner bundle, and valve controlled means responsive to pressure conditions in the cooler for connecting said second chamber with said outlet fitting.

JOSEPH ASKIN. 

